1. Field of the Invention
The invention relates to a coating method for a color filter and an aligning-assembling method for a color wheel and, in particular, to the coating method for the color filter and the aligning-assembling method for the color wheel, both of which are used in projection technology.
2. Description of the Related Art
In recent years, demand has arisen for a color filter used in a device such as a liquid crystal display or a color wheel. The color filter separates the light into three fundamental colors (i.e. red, green and blue), and then the color filter further mixes these three fundamental colors to create the different colors in different ratios.
In general, coating three fundamental colors on a substrate makes the color filter. The shape, the size and the arrangement of the color filter are adjusted according to practical needs. For example, the color filter is composed of three sectors of red, green and blue. Also, the color filter is a ring-shaped filter composed of one transparent block and three or more filter sectors of red, green and blue.
In the conventional color filter coating technology, a pattern on a mask is transferred to a glass substrate by exposure and development. Herein, the position of the mask and the substrate is aligned by mechanical alignment. Because the accuracy of the mechanical alignment is insufficient, the error in the coating position may increase. Further, the reliability of the color filter may also decrease.
In addition, the color wheel 6 mainly includes a motor 61 and a color filter 62. As shown in FIG. 1, the color filter 62 is mounted on the axis of the motor 61. The color filter 62 rotates together with the motor 61 and generates the light rays of several colors.
In the conventional aligning-assembling method for the color wheel, the color filter and the motor are set on the fixing jig, and then both of them are aligned by a mechanical method. After alignment, the color filter and the motor are assembled to create the color wheel. Generally, the motor rotates at a speed higher than 7200 rpm. When the rotation center of the motor is away from the central axis of the rotation shaft (i.e., when the rotation center is not located on the central axis of the rotation shaft), the operation of the color wheel may be adversely influenced by vibration and noise. Further, the operational reliability of the color wheel may decrease. For above-mentioned reasons, the accuracy of aligning the color wheel is very critical. However, the accuracy of the mechanical alignment is insufficient, and the speed of the mechanical alignment is also very slow. Therefore, the mechanical alignment is inapplicable in industrial applications.
It is therefore an important objective of the invention to provide a coating method for the color filter and an aligning-assembling method for the color wheel to solve the above-mentioned problem.